This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-149800, filed May 28, 1999; and No. 2000-048220, filed Feb. 24, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a silver halide color photosensitive material and, more particularly, to a silver halide color photosensitive material having improved color reproduction.
Recently, silver halide color photosensitive materials are strongly required to have superior color reproduction in addition to high sensitivity with which photographing is possible, high sharpness, and high graininess.
In particular, purplish colors which reflect light having longer wavelengths than 580 nm are reproduced as colors much more reddish than the actual ones. It is pointed out that one cause of this inconvenience is that the maximum sensitivity wavelength of the spectral sensitivity distribution of red-sensitive layers of many color photosensitive materials for photographing, e.g., many color reversal films, is much longer than 605 nm (in many cases longer than 640 nm) which is the wavelength of the spectral sensitivity peak of the longest wavelength of three sensory organs of the human eye. For the purposes of obtaining faithful color reproduction and providing a photographing sensitive material which does not largely changes its color reproduction during photographing under various light sources, U.S. Pat. No. 3,672,898 has disclosed a method of restricting the spectral sensitivity distributions of blue-, green-, and red-sensitive layers to certain ranges. According to this patent, purplish hue reproduction can be effectively improved by shifting the spectral sensitivity distribution of a red-sensitive layer to a shorter wavelength and approaching the maximum sensitivity wavelength of the spectral sensitivity distribution of that red-sensitive layer to 605 nm.
Unfortunately, the following problems arise in providing a color film which faithfully reproduces the hue and perceived chroma of an object to be photographed by shifting the spectral sensitivity distribution of a red-sensitive layer to a shorter wavelength.
First, when the spectral sensitivity wavelength of a red-sensitive layer is shortened, purple is faithfully reproduced. However, the sensitivity of this red-sensitive emulsion layer to red light becomes insufficient, so the color reproduction of red becomes cyanic and this lowers the saturation. As a method of solving this problem and improving both the saturation and the hue reproduction, Jpn. Pat. Appln. KOKAI Publication No. (hereafter referred to as JP-A-)62-49354, whose corresponding U.S. application is now patented to U.S. Pat. No. 4,764,456, has disclosed a method of using pyrazoloazole couplers as magenta couplers. Also, JP-A-2-124566 has proposed a method of improving saturation by enhancing the interlayer effect to red-sensitive emulsion layers in a color reversal photosensitive material, thereby improving both hue and faithfulness. Furthermore, in examples of this publication the use of 2-equivalent pyrazolotriazole couplers is described.
When, however, the present inventors examined the application of 2-equivalent pyrazoloazole couplers to color reversal photosensitive materials, it turned out that the saturation of red did not improve as expected and green became impure to lower its saturation when 2-equivalent pyrazoloazole couplers were used in green-sensitive layers, compared to conventionally used 4-equivalent pyrazolone magenta couplers. When the spectral sensitivity of a red-sensitive emulsion layer is shortened, the saturation of red and green naturally lowers. Therefore, a further lowering of the saturation of green is a serious problem when the spectral sensitivity wavelength of a red-sensitive emulsion layer is relatively shortened.
A method which uses an asymmetrical trimethinecyanine dye (e.g., one is a benzoxazole derivative and the other is a benzothiazole derivative) as represented by formula (I) described in JP-A-2-124566, whose corresponding U.S. application is now patented to U.S. Pat. No. 5,024,925, is an effective means for shortening the wavelength of the spectral sensitivity distribution of a red-sensitive layer. Also, JP-A-62-49354 describes in its examples the combined use of sensitizing dyes in this category and 2-equivalent pyrazoloazole couplers. However, when the present inventors used 2-equivalent pyrazoloazole magenta couplers and also used large amounts of sensitizing dyes effective to wavelength shortening in in red-sensitive layers, the sensitizing dyes remained after development and colored white portions. Since coloration of white portions in particularly color reversal photosensitive materials largely impairs the product value, coloration after processing is unallowable, so a certain solution is being strongly demanded. On the other hand, the use of 4-equivalent pyrazoloazole couplers in color reversal photosensitive materials is disclosed in, e.g., JP-A-63-153548, whose corresponding U.S. application is now patented to U.S. Pat. No. 4,994,351. However, this JP-A-63-153548 has not disclosed the difference between the color reproduction effects of 2- and 4-equivalent couplers and the combination of these couplers with the aforementioned sensitizing dyes. That is, the problems which the present inventors encountered, i.e., the problem of color reproduction of 2-equivalent pyrazoloazole couplers or of the combination of 2- and 4-equivalent pyrazoloazole couplers and the problem of coloration of white portions caused by residual sensitizing dyes are unknown problems.
It is an object of the present invention to provide a silver halide color photosensitive material having improved reproduction of hue and perceived chroma and, more specifically, to apply this material to a color reversal photosensitive material which is subjected to reversal processing and color development after black-and-white development.
The above object of the present invention is achieved by the following.
(1) A silver halide color photosensitive material having at least one blue-sensitive emulsion layer, at least one green-sensitive emulsion layer, and at least one red-sensitive emulsion layer on a support, wherein the red-sensitive emulsion layer has the maximum value of sensitivity in a wavelength region of 580 nm to 650 nm, and the green-sensitive emulsion layer contains at least one magenta coupler represented by formula (MC-1) below: 
wherein R1 represents a substituent selected from the group consisting of a secondary or tertiary alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group, an acylamino group, an arylthio group, an alkylthio group, an aminocarbonylamino group, an alkoxycarbonylamino group, a carbamoyloxy group, and a heterocyclic thio group. These substituents may be substituted or unsubstituted. Each of G1 and G2 represents a nitrogen atom or a carbon atom. When G1 is a nitrogen atom, G2 is a carbon atom; when G2 is a nitrogen atom, G1 is a carbon atom. R2 substitutes one of G1 and G2 which is a carbon atom, and represents a substituent. A group represented by formula (MC-1) can further substitute via R1 or R2 to form a polymer. Also, a group represented by formula (MC-1) can bond to a polymer chain via R1 or R2.
(2) A silver halide color photosensitive material having at least one blue-sensitive emulsion layer, at least one green-sensitive emulsion layer, and at least one red-sensitive emulsion layer on a support, wherein the red-sensitive emulsion layer contains a sensitizing dye represented by formula (SD-1) below at a molar ratio of 10% to 100% with respect to all the sensitizing dyes in the layer, and the green-sensitive emulsion layer contains at least one magenta coupler represented by formula (MC-1) described in item (1): 
wherein Z1 represents an atomic group necessary to form a heterocyclic ring selected from the group consisting of substituted or nonsubstituted benzoimidazole, benzoxazole, and naphthoxazole. Z2 represents an atomic group necessary to form a heterocyclic ring selected from the group consisting of substituted or nonsubstituted benzothiazole, benzoselenazole, naphthothiazole, naphthoselenazole, and benzotellurazole. Each of A1 and A2 represents a substituted or nonsubstituted alkyl group. A3 represents a hydrogen atom, an alkyl group, or an aryl group. X represents a cation, and n is 1 or 2. n is 1 when an intramolecular salt is to be formed.
(3) A silver halide color photosensitive material having at least one blue-sensitive emulsion layer, at least one green-sensitive emulsion layer, and at least one red-sensitive emulsion layer on a support, wherein a quality factor indicating the consistency between the spectral sensitivity of the red-sensitive emulsion layer and the color sensitivity of a human is 0.9 or more, and the green-sensitive emulsion layer contains at least one type of a magenta coupler represented by formula (MC-1) described in item (1).
(4) The silver halide color photosensitive material described in item (2), wherein the red-sensitive emulsion layer has the maximum value of sensitivity in a wavelength region of 580 to 650 nm, or a quality factor indicating the consistency between the spectral sensitivity of the red-sensitive emulsion layer and the color sensitivity of a human is 0.9 or more.
(5) A silver halide color photosensitive material having at least one blue-sensitive emulsion layer, at least one green-sensitive emulsion layer, and at least one red-sensitive emulsion layer on a support, wherein the silver halide color photosensitive material further has a photosensitive silver halide emulsion layer which does not substantially generate an image dye but imparts the interimage effect to another layer, and the green-sensitive emulsion layer contains at least one magenta coupler represented by formula (MC-1) described in item (1).
The present invention will be described in detail below.
First, formula (MC-1) will be explained.
In formula (MC-1), R1 represents a substituent selected from the group consisting of a secondary or tertiary alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group, an acylamino group, an arylthio group, an alkylthio group, an aminocarbonylamino group, an alkoxycarbonylamino group, a carbamoyloxy group, and a heterocyclic thio group. These substituents can have a substituent. Examples of this substituent are groups represented by R2 to be described later.
Specific examples of R1 are a secondary or tertiary alkyl group (e.g., isopropyl, t-butyl, t-amyl, adamantyl, 1-methylcylopropyl, t-octyl, cyclohexyl, 2-methanesulfonylethyl, 3-(3-pentadecylphenoxy)propyl, 3-{4-{2-[4-(4-hydroxyphenylsulfonyl)phenoxy]dodecaneamido}phenyl}propyl, 2-ethoxytridecyl, trifluoromethyl, cyclopentyl, 3-(2,4-di-t-amylphenoxy)propyl, benzyl, 4-methoxybenzyl, and 2-methoxybenzyl), an aryl group (e.g., phenyl, 4-t-butylphenyl, 2,4-di-t-amylphenyl, and 4-tetradecaneamidophenyl), an alkoxy group (e.g., methoxy, ethoxy, 2-methoxyethoxy, 2-dodecylethoxy, 2-methanesulfonylethoxy, and 2-phenoxyethoxy), an aryloxy group (e.g., phenoxy, 2-methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy, 3-t-butyloxycarbamoylphenoxy, and 3-methoxycarbamoylhpenoxy), an amino group (including an anilino group; e.g., methylamino, ethylamino, anilino, dimethylamino, diethylamino, t-butylamino, 2-methoxyanilino, 3-acetylaminoanilino, and cyclohexylamino), an acylamino group (e.g., acetamide, benzamide, tetradecaneamide, 2-(2,4-di-t-amylphenoxy)butaneamide, 4-(3-t-butyl-4-hydroxyphenoxy)butaneamide, and 2-{4-(4-hydroxyphenylsulfonyl)phenoxy}decaneamide), an aminocarbonylamino group (e.g., carbamoylamino, N,N-dimethylaminocarbonylamino, and morpholinocarbonylamino), an alkylthio group (e.g., methylthio, octylthio, tetradecylthio, 2-phenoxyethylthio, 3-phenoxypropylthio, and 3-(4-t-butylphenoxy)propylthio), an arylthio group (e.g., phenylthio, 2-butoxy-5-t-octylphenylthio, 3-pentadecylphenylthio, 2-carboxyphenylthio, and 4-tetradecaneamidophenylthio), an alkoxycarbonylamino group (e.g., methoxycarbonylamino and tetradecyloxycarbonylamino), a carbamoyloxy group (e.g., N-methylcarbamoyloxy and N-phenylcarbamoyloxy), and a heterocyclic thio group (e.g., 2-benzothiazolylthio, 2,4-di-phenoxy-1,3,5-triazole-6-thio, and 2-pyridylthio).
Of these substituents, a secondary or tertiary alkyl group having a total number of carbon atoms of 3 to 30, an aryl group, an alkoxy group, an aryloxy group, and an amino group are preferable, a secondary or tertiary alkyl group having a total number of carbon atoms of 3 to 15 is more preferable, and a tertiary alkyl group having a total number of carbon atoms of 4 to 10 is most preferable.
One of G1 and G2 is a nitrogen atom, the other is a carbon atom, and R2 in formula (MC-1) substitutes one of G1 and G2 which is a carbon atom.
R2 represents a substituent. Examples of this substituent are a halogen atom, alkyl group, aryl group, heterocyclic group, cyano group, hydroxyl group, nitro group, carboxyl group, amino group, alkoxy group, aryloxy group, acylamino group, alkylamino group, anilino group, aminocarbonylamino group, sulfamoylamino group, alkylthio group, arylthio group, alkoxycarbonylamino group, sulfonamide group, carbamoyl group, sulfamoyl group, sulfonyl group, alkoxycarbonyl group, heterocyclic oxy group, azo group, acyloxy group, carbamoyloxy group, silyloxy group, aryloxycarbonylamino group, imide group, heterocyclic thio group, sulfinyl group, phosphonyl group, aryloxycarbonyl group, acyl group, and azolyl group. These substituents can have a substituent.
More specifically, examples of the substituent represented by R2 are a halogen atom (e.g., a chlorine atom and a bromine atom), an alkyl group {e.g., a straight-chain or branched-chain alkyl group, and a cycloalkyl group (more specifically, methyl, ethyl, propyl, isopropyl, t-butyl, tridecyl, 2-methanesulfonylethyl, 3-(3-pentadecylphenoxy)propyl, 3-{4-{2-[4-(4-hydroxyphenylsulfonyl)phenoxy]dodecaneamido}phenyl}propyl, 2-ethoxytridecyl, trifluoromethyl, cyclopentyl, and 3-(2,4-di-t-amylphenoxy)propyl)), an alkenyl group (e.g. vinyl, allyl and prenyl), an alkinyl group (e.g. ethynyl and propargyl)}, an aryl group (e.g., phenyl, 4-t-butylphenyl, 2,4-di-t-amylphenyl, and 4-tetradecaneamidophenyl), a heterocyclic group (e.g., 2-furyl, 2-thienyl, 2-pyrimidinyl, and 2-benzothiazolyl), a cyano group, a hydroxyl group, a nitro group, a carboxyl group, an amino group, an alkoxy group (e.g., methoxy, ethoxy, 2-methoxyethoxy, 2-dodecylethoxy, and 2-methanesulfonylethoxy), an aryloxy group (e.g., phenoxy, 2-methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy, 3-t-butyloxycarbamoylphenoxy, and 3-methoxycarbamoylphenoxy), an acylamino group (e.g., acetamide, benzamide, tetradecaneamide, 2-(2,4-di-t-amylphenoxy)butaneamide, 4-(3-t-butyl-4-hydroxyphenoxy)butaneamide, 2-{4-(4-hydroxyphenylsulfonyl)phenoxy}decaneamide), an alkylamino group (e.g., methylamino, butylamino, dodecylamino, diethylamino, and methylbutylamino), an anilino group (e.g., phenylamino, 2-chloroanilino, 2-chloro-5-tetradecaneaminoanilino, 2-chloro-5-dodecyloxycarbonylanilino, N-acetylanilino, and 2-chloro-5-{a-(3-t-butyl-4-hydroxyphenoxy)dodecaneamido}anilino), a ureido group (e.g., phenylureido, methylureido, and N,N-dibutylureido), sulfamoylamino group (e.g., N,N-dipropylsulfamoylamino and N-methyl-N-decylsulfamoylamino), an alkylthio group (e.g., methylthio, octylthio, tetradecylthio, 2-phenoxyethylthio, 3-phenoxypropylthio, and 3-(4-t-butylphenoxy)propylthio), an arylthio group (e.g., phenylthio, 2-butoxy-5-t-octylphenylthio, 3-pentadecylphenylthio, 2-carboxyphenylthio, and 4-tetradecaneamidophenylthio), an alkoxycarbonylamino group (e.g., methoxycarbonylamino and tetradecyloxycarbonylamino), a sulfonamide group (e.g., methanesulfonamide, hexadecanesulfonamide, benzenesulfonamide, p-toluenesulfonamide, octadecanesulfonamide, 2-methyloxy-5-t-butylbenzenesulfonamide), a carbamoyl group (e.g., N-ethylcarbamoyl, N,N-dibutylcarbamoyl, N-(2-dodecyloxyethyl)carbamoyl, N-methyl-N-dodecylcarbamoyl, and N-(3-(2,4-di-t-amylphenoxy)propyl)carbamoyl), a sulfamoyl group (e.g., N-ethylsulfamoyl, N,N-dipropylsulfamoyl, N- (2-dodecyloxyethyl)sulfamoyl, N-ethyl-N-dodecylsulfamoyl, and N,N-diethylsulfamoyl), a sulfonyl group (e.g., methanesulfonyl, octanesulfonyl, benzenesulfonyl, and toluenesulfonyl), an alkoxycarbonyl group (e.g., methoxycarbonyl, butyloxycarbonyl, dodecyloxycarbonyl, and octadecyloxycarbonyl), a heterocyclic oxy group (e.g., 1-phenyltetrazole-5-oxy and 2-tetrahydropyranyloxy), an azo group (e.g., phenylazo, 4-methoxphenylazo, 4-pyvaloylaminophenylazo, and 2-hydroxy-4-propanoylphenylazo), an acyloxy group (e.g., acetoxy), a carbamoyloxy group (e.g., N-methylcarbamoyloxy and N-phenylcarbamoyloxy), a silyloxy group (e.g., trimethylsilyloxy and dibutylmethylsilyloxy), an aryloxycarbonylamino group (e.g., phenoxycarbonylamino), an imide group (e.g., N-succinimide, N-phthalimide, and 3-octadecenylsuccinimide), a heterocyclic thio group (e.g., 2-benzothiazolylthio, 2,4-di-phenoxy-1,3,5-trizole-6-thio, and 2-pyridylthio), a sulfinyl group (e.g., dodecanesulfinyl, 3-pentadecylphenylsulfinyl, and 3-phenoxypropylsulfinyl), a phosphonyl group (e.g., phenoxyphosphonyl, octyloxyphosphonyl, and phenylphosphonyl), an aryloxycarbonyl group (e.g., phenoxycarbonyl), an acyl group (e.g., acetyl, 3-phenylpropanoyl, benzoyl, and 4-dodecyloxybenzoyl), and an azolyl group (e.g., imidazolyl, pyrazolyl, 3-chloro-pyrazole-1-yl, and triazole).
A group in which a group represented by R2 can further have a substituent can further have an organic substituent, which couples by a carbon atom, oxygen atom, nitrogen atom, or sulfur atom, or a halogen atom.
Preferable examples of R2 are an alkyl group, aryl group, alkoxy group, aryloxy group, alkylthio group, ureido group, alkoxycarbonylamino group, and acylamino group. Furthermore, R2 is preferably a group having a total number of carbon atoms of 6 to 70, which contains a 6- to 70-carbon alkyl group or an aryl group as a partial structure, and preferably gives immobility to a coupler represented by formula (MC-1). In the specification, the phrase xe2x80x9ca substituent having an alkyl group as a partial structurexe2x80x9d includes the case where the substituent itself is the alkyl group, as well as the substituent has the alkyl group as a further substituent, if possible. The same can be applied to xe2x80x9ca substituent having an aryl group (or another group) as a partial structurexe2x80x9d, if possible. That is, xe2x80x9ca group having an aryl group as a partial structurexe2x80x9d includes the case where the group as a whole is the aryl group, as well as the group is substituted with the aryl group, if possible.
In formula (MC-1), R2 is more preferably a compound which is a substituent represented by formula (BL-1) or (BL-2) below: 
In formula (BL-1), each of R3, R4, R5, R6, and R7 independently represents a hydrogen atom or a substituent, and at least one of them represents a substituent having a total number of carbon atoms of 4 to 70 and containing a substituted or nonsubstituted alkyl group as a partial structure, or a substituent having a total number of carbon atoms of 6 to 70 and containing a substituted or nonsubstituted aryl group as a partial structure.
A group represented by formula (BL-1) will be described below.
Each of R3, R4, R5, R6, and R7 independently represents a hydrogen atom or a substituent. Examples of this substituent are those enumerated above for R2. At least one of R3, R4, R5, R6, and R7 is a substituent having a total number of carbon atoms of 4 to 70 and containing a substituted or nonsubstituted alkyl group as a partial structure, or a substituent having a total number of carbon atoms of 6 to 70 and containing a substituted or nonsubstituted aryl group as a partial structure. Preferable examples are an alkoxy group, an aryloxy group, an acylamino group, an aminocarbonylamino group, a carbamoyl group, an alkoxycarbonylamino group, a sulfonyl group, a sulfonamide group, a sulfamoyl group, a sulfamoylamino group, an alkoxycarbonyl group, an alkyl group, and an aryl group, each having a total number of carbon atoms of 4 (6 if an aryl group is contained) to 70 and containing a substituted or nonsubstituted alkyl or aryl group as a partial structure. Of these substituents, an alkyl group having a total number of carbon atoms of 4 to 70, an alkoxy group having a total number of carbon atoms of 4 to 70 and containing an alkyl group as a partial structure, an alkoxycarbonyl group having a total number of carbon atoms of 4 to 70 and containing an alkyl group as a partial structure, ian acylamino group having a total number of carbon atoms of 4 to 70 and containing an alkyl group as a partial structure, and sulfonamide group having a total number of carbon atoms of 4 to 70 and containing an alkyl group as a partial structure are preferable.
In formula (BL-2), G3 represents a substituted or nonsubstituted methylene group, a represents an integer from 1 to 3, R8 represents a hydrogen atom, an alkyl group, or an aryl group, G4 represents xe2x80x94COxe2x80x94 or xe2x80x94SO2xe2x80x94, Rg represents a substituent having a total number of carbon atoms of 6 to 70 and containing a substituted or nonsubstituted alkyl or aryl group as a partial structure. If R9 has a substituent, examples of this substituent are those enumerated above for R2. If a is 2 or more, a plurality of G3""s can be the same or different. Preferably, a group represented by (G3)a is xe2x80x94CH2xe2x80x94, C(CH3)Hxe2x80x94, xe2x80x94C(CH3)2xe2x80x94, xe2x80x94C(i-C3H7)Hxe2x80x94, xe2x80x94C2H4xe2x80x94, xe2x80x94C(CH3)Hxe2x80x94CH2xe2x80x94, xe2x80x94C(CH3)2xe2x80x94CH2xe2x80x94, xe2x80x94C(CH3)2xe2x80x94C(CH3)Hxe2x80x94, or xe2x80x94C(CH3)Hxe2x80x94C(CH3)Hxe2x80x94, R8 is a hydrogen atom, G4 is xe2x80x94COxe2x80x94 or xe2x80x94SO2xe2x80x94, R9 is a substituted or nonsubstituted alkyl or aryl group having a total number of carbon atoms of 10 to 70.
In a compound represented by formula (MC-1), if G1 is a nitrogen atom and G2 is a carbon atom, it is preferable that R1 be a tertiary alkyl group, R2 be a group represented by formula (BL-1), and each of R4 and R6 be a group selected from the group consisting of an acylamino group, a sulfonamide group, a ureido group, an alkoxycarbonylamino group, a sulfonyl group, a carbamoyl group, a sulfamoyl group, a sulfamoylamino group, and an alkoxycarbonyl group, each having a total number of carbon atoms of 4 or more and 70 or less and to each of which a substituted or nonsubstituted alkyl group is attached, and an acylamino group, a sulfonamide group, a ureido group, an alkoxycarbonylamino group, a sulfonyl group, a carbamoyl group, a sulfamoyl group, a sulfamoylamino group, and an alkoxycarbonyl group, each having a total number of carbon atoms of 6 or more and 70 or less and to each of which a substituted or nonsubstituted aryl group is attached.
If G1 is a carbon atom and G2 is a nitrogen atom in a compound represented by formula (MC-1), it is preferable that R1 be a tertiary alkyl group and R2 be a group represented by formula (BL-1) or (BL-2). Most preferably, R2 is a group represented by formula (BL-2) or a group represented by formula (BL-1) in which each of R3 and R7 is a 1- to 6-carbon alkyl group and at least one of R4, R5, and R6 is a group having a total number of carbon atoms of 6 to 70, and containing a substituted or nonsubstituted alkyl or aryl group as a partial structure.
In the present invention, it is preferable that G1 be a carbon atom, G2 be a nitrogen atom, R1 be a tertiary alkyl group, and R2 be represented by formula (BL-2) in which G4 is xe2x80x94SO2xe2x80x94, R9 is a phenyl group having at least one group containing a 6- to 50-carbon alkyl group as a substituent, and a is 1 or 2. Most preferably, R9 is a group further having a group selected from xe2x80x94OH, xe2x80x94SO2NH2, xe2x80x94SO2NHR10, xe2x80x94NHSO2R10, xe2x80x94SO2NHCOR10, xe2x80x94COOH, and xe2x80x94CONH2 as a partial structure. R10 represents a substituted or nonsubstituted alkyl group or aryl group. If R10 is an aryl group, this aryl group is preferably a phenyl group, and this phenyl group preferably substitutes at least one electron attracting group. Preferable examples of this electron attracting group are a halogen atom, cyano group, alkyl halide group, aryl halide group, acyl group, carbamoyl group, alkyloxycarbonyl, aryloxycarbonyl group, sulfonyl group, alkylaminosulfonyl or arylaminosulfonyl group.
If R10 is an alkyl group, this alkyl group is preferably a 1- to 50-carbon (more preferably, 1- to 30-carbon), substituted or nonsubstituted, straight-chain or branched alkyl group.
If a coupler represented by formula (MC-1) forms a polymer, this polymer is preferably a dimer, trimer, or tetramer, and most preferably, a dimer. Also, if this coupler bonds to a polymer chain, the total molecular weight is preferably 8,000 to 50,000, and the molecular weight per coupler nucleus is preferably 500 to 1,000.
Practical compound examples of formula (MC-1) will be presented below, but the present invention is not limited to these practical examples. 
The coupler represented by formula (MC-1) of the present invention can be synthesized by know methods. Examples are described in U.S. Pat. Nos. 4,540,654, 4,705,863, and 5,451,501, JP-A""s-61-65245, 62-209457, 62-249155, 63-41851, Jpn. Pat. Appln. KOKOKU Publication No. (hereinafter referred to as JP-B-)7-122744, JP-B""s-5-105682, 7-13309, 7-82252, U.S. Pat. Nos. 3,725,067 and 4,777,121, JP-A""s-2-201442, 2-101077, 3-125143, and 4-242249, the disclosures of which are herein incorporated by reference.
The coupler represented by formula (MC-1) of the present invention can be introduced to a sensitive material by various known dispersion methods. Of these methods, an oil-in-water dispersion method is preferable in which a coupler is dissolved in a high-boiling organic solvent (used in combination with a low-boiling solvent where necessary), the solution is dispersed by emulsification in an aqueous gelatin solution, and the dispersion is added to a silver halide emulsion.
Examples of the high-boiling solvent used in this oil-in-water dispersion method are described in, e.g., U.S. Pat. No. 2,322,027, the disclosure of which is herein incorporated by reference. Practical examples of steps, effects, and impregnating latexes of a latex dispersion method as one polymer dispersion method are described in, e.g., U.S. Pat. No. 4,199,363, West German Patent Application (OLS) Nos. 2,541,274 and 2,541,230, JP-B-53-41091, and EP029104, the disclosures of which are herein incorporated by reference. Dispersion using an organic solvent-soluble polymer is described in PCT International Publication W088/00723, the disclosure of which is herein incorporated by reference.
Examples of the high-boiling solvent usable in the abovementioned oil-in-water dispersion method are phthalic acid esters (e.g., dibutylphthalate, dioctylphthalate, dicyclohexylphthalate, di-2-ethylhexylphthalate, decylphthalate, bis(2,4-di-tert-amylphenyl)isophthalate, and bis(1,1-diethylpropyl)phthalate), esters of phosphoric acid and phosphonic acid (e.g., diphenylphosphate, triphenylphosphate, tricresylphosphate, 2-ethylhexyldiphenylphosphate, dioctylbutylphosphate, tricyclohexylphosphate, tri-2-ethylhexylphosphate, tridodecylphosphate, and di-2-ethylhexylphenylphosphate), benzoic acid esters (e.g., 2-ethylhexylbenzoate, 2,4-dichlorobenzoate, dodecylbenzoate, and 2-ethylhexyl-p-hydroxybenzoate), amides of aliphatic carboxylic acid (e.g., N,N-diethyldodecaneamide and N,N-diethyllaurylamide), amides of aromatic carboxylic acid (e.g., 2-dodecyloxy benzoic acid amide, N,N,N,N-tetracyclohexylisophthalic acid amide, and N,N,N,N-tetra-2-ethylhexylisophthalic acid amide), alcohols and phenols (e.g., isostearylalcohol and 2,4-di-tert-amylphenol), aliphatic esters (e.g., dibutoxyethyl succinate, di-2-ethylhexyl succinate, 2-hexyldecyl tetradecanate, tributyl citrate, diethylazelate, isostearyllactate, and trioctyltosylate), aniline derivatives (e.g., N,N-dibutyl-2-butoxy-5-tert-octylaniline), chlorinated paraffins (paraffins containing 10% to 80% of chlorine), trimesic acid esters (e.g., trimesic acid tributyl), dodecylbenzene, diisopropylnaphthalene, phenols (e.g., 2,4-di-tert-amylphenol, 4-dodecyloxyphenol, 4-dodecyloxycarbonylphenol, and 4-(4-dodecyloxyphenylsulfonyl)phenol), carboxylic acids (e.g., 2-(2,4-di-tert-amylphenoxy butyric acid and 2-ethoxyoctanedecanic acid), alkylphosphoric acids (e.g., di-(2-ethylhexyl)phosphoric acid and diphenylphosphoric acid). In addition to the above high-boiling solvents, compounds described in, e.g., JP-A-6-258803, the disclosure of which is herein incorporated by reference, can also be preferably used as high-boiling solvents.
Of these compounds, phosphoric acid esters and amides of aromatic carboxylic acid are preferable, and the combination of phosphoric acid esters and amides of aromatic carboxylic acid with alcohols or phenols is also preferable.
In the present invention, the weight ratio of a high-boiling organic solvent to the coupler represented by formula (MC-1) is preferably 0 to 2.0, more preferably, 0.01 to 1.0, and most preferably, 0.01 to 0.5.
As a co-solvent, it is also possible to use an organic solvent (e.g., ethyl acetate, butyl acetate, ethyl propionate, methylethylketone, cyclohexanone, 2-ethoxyethylacetate, and dimethylformamide) having a boiling point of 30xc2x0 C. to about 160xc2x0 C.
The content of the coupler represented by formula (MC-1) of the present invention in a sensitive material is 0.01 to 10 g, preferably 0.1 g to 2 g per m2. The content is appropriately 1xc3x9710xe2x88x923 to 1 mol, preferably 2xc3x9710xe2x88x923 to 3xc3x9710xe2x88x921 mol per mol of a silver halide in the same sensitive emulsion layer.
It is also preferable to use the coupler represented by formula (MC-1) of the present invention together with a pyrazolotriazole coupler in which the arrangement of the carbon and nitrogen atoms represented by G1 and G2 in formula (MC-1) is opposite to the former coupler. The ratio of the former coupler represented by formula (MC-1): the latter coupler, can arbitrary be selected from 1:99 to 99:1 as a molar ratio, and the ratio is preferably 20:80 to 80:20. It is particularly preferable that a coupler in which G1 and G2 are a carbon atom and a nitrogen atom, respectively, in formula (MC-1) of the present invention account for 50% to 90%, as a molar ratio, of the total pyrazolotriazole coupler amount in the layer, and the rest be a pyrazolo-(1,5-b)-1,2,4-triazole coupler.
When a sensitive layer has a unit configuration including two or more sensitive emulsion layers having the same color sensitivity but differing in speed, the coupler content of the present invention per mol of a silver halide is preferably 2xc3x9710xe2x88x923 to 1xc3x9710xe2x88x921 mol in a low-speed layer and 3xc3x9710xe2x88x922 to 3xc3x9710xe2x88x921 mol in a high-speed layer.
The present invention is characterized by containing the magenta coupler represented by formula (MC-1). Although another magenta coupler can also be used together with this coupler, the results become more preferable as the ratio of a color dye of a coupler represented by formula (MC-1) of the present invention in the contribution to the total magenta density increases. More specifically, the amount is such that the coupler represented by formula (MC-1) of the present invention accounts for preferably 20% or more, more preferably, 40% or more, and most preferably, 70% or more, as a molar ratio with respect to all the magenta couplers contained in the photosensitive material of the invention.
A sensitive material of the present invention can also contain a competing compound (a compound which competes with an image forming coupler to react with an oxidized form of a color developing agent and which does not form any dye image). Examples of this competing coupler are reducing compounds such as hydroquinones, catechols, hydrazines, and sulfonamidophenols, and compounds which couple with an oxidized form of a color developing agent but do not substantially form a color image (e.g., colorless compound-forming couplers disclosed in German Patent No. 1,155,675, British Patent No. 861,138, and U.S. Pat. Nos. 3,876,428 and 3,912,513, and flow-out couplers disclosed in JP-A-6-83002, the disclosures of which are herein incorporated by reference).
The competing compound is preferably added to a sensitive emulsion layer containing a magenta coupler represented by formula (MC-1) of the present invention or a non-sensitive layer. The completing compound is particularly preferably added to a sensitive emulsion layer containing a coupler represented by formula (MC-1) of the present invention. The content of a competing compound is 0.01 to 10 g, preferably 0.10 to 5.0 g per m2 of a sensitive material. The content is 1 to 1,000 mol %, preferably 20 to 500 mol % with respect to the coupler represented by formula (MC-1) of the present invention.
In a sensitive material of the present invention, a sensitive unit sensitive to the same color can have a non-color-forming interlayer. Additionally, this interlayer preferably contains a compound selectable as the aforementioned competing compound.
To prevent deterioration of the photographic properties caused by formaldehyde gas, the sensitive material of the present invention preferably contains a compound described in U.S. Pat. Nos. 4,411,987 or 4,435,503, which can react with and fix formaldehyde gas.
The spectral sensitivity of a red-sensitive layer preferable to the present invention will be described below.
In the present invention, a spectral sensitivity distribution is obtained as follows. That is, a sensitive material with which a support is coated is exposed to equal-energy spectral light, described in JIS Z-8105, 2018, from 400 up to 700 nm, and processed by developing steps described in examples of this specification. The yellow, magenta, and cyan (status A) densities of the obtained image are measured, and the reciprocal of an exposure amount which gives a constant density at each wavelength is defined as the sensitivity at that wavelength. This sensitivity is used as a function of the wavelength.
In the present invention, a red-sensitive layer has the maximum value of sensitivity within the range of 580 to 650 nm (in this specification, this sensitivity is the one which gives a density of 1.0 in equal-energy spectral exposure unless otherwise specified. The density is measured by the status A. The spectral sensitivity distributions of blue-, green-, and red-sensitive emulsion layers are obtained by measuring the yellow, magenta, and cyan densities, respectively). A red-sensitive layer has the maximum value of sensitivity within the range of preferably 600 to 640 nm (more preferably, 610 to 635 nm).
Also, the sensitivity at 600 nm is preferably ⅓ or more (more preferably, xc2xd or more) of the sensitivity at the wavelength which gives the maximum value of sensitivity. The sensitivity at 670 nm is preferably {fraction (1/10)} or less of the sensitivity at the wavelength which gives the maximum value of sensitivity.
A red-sensitive layer in the sensitive material of the present invention can have a plurality of peak points, i.e., a maximum point and at least one peak point, in its spectral sensitivity distribution. Herein, the maximum point gives a higher sensitivity than the peak point. For example, a red-sensitive layer can have a maximum point which gives the maximum value of sensitivity and a sensitivity peak point at a shorter wavelength or a longer wavelength than the wavelength giving the maximum sensitivity. When a red-sensitive layer has such a maximum point and a peak point, it is preferable that the maximum point which gives the maximum value of sensitivity be within the range of 630 to 650 nm and the peak point be within the range of 590 to 620 nm. It is also preferable that the peak point be within the range of 650 to 670 nm.
The spectral sensitivity of a red-sensitive layer of the present invention is preferably such that the maximum value of sensitivity exists at a wavelength of 600 to 640 nm, the sensitivity at 600 nm is ⅓ or more of the sensitivity at the wavelength which gives the maximum value of sensitivity, and the sensitivity at 670 nm is {fraction (1/10)} or less of the sensitivity at the wave-length which gives the maximum value of sensitivity.
A quality factor representing the consistency between the spectral sensitivity described in the present invention and the human color sensitivity is a colorimetric quality factor (q factor) described in, e.g., xe2x80x9cJournal of The Optical Society of Americaxe2x80x9d, Vol. 46, pp. 821 to 824 (1956) or xe2x80x9cJournal of Japan Photographic Societyxe2x80x9d, Vol. 61, No. 1, pp. 8 to 17 (1998), the disclosures of which are herein incorporated by reference. This q factor is known as an index which represents the consistency between spectral sensitivity and color matching functions (described in, e.g., xe2x80x9cJournal of The Optical Society of Americaxe2x80x9d, Vol. 43, p. 533 ff. (1953), the disclosure of which is herein incorporated by reference). The q factor can be calculated by the method described in xe2x80x9cJournal of Japan Photographic Societyxe2x80x9d, Vol. 61, No. 1, p. 9 (1998), the disclosure of which is herein incorporated by reference. In the present invention, the g factor of a red-sensitive layer is 0.90 or more. However, the g factors of both green- and blue-sensitive layers are also preferably 0.90 or more.
A sensitizing dye used in the sensitive material of the present invention will be described below. The spectral sensitivity of the present invention is preferably achieved by using a compound represented by formula (SD-1) as a sensitizing dye.
IVA sgDetails of this compound represented by formula (SD-1) will be described below.
First, A1 and A2 will be explained. Each of A1 and A2 represents a substituted or nonsubstituted alkyl group (e.g., a 1- to 10-carbon alkyl group and a 7 to 12-total carbon alkyl group substituted with an aryl group; specifically, methyl, ethyl, n-propyl, i-propyl, n-butyl, 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 5-sulfopentyl, carboxymethyl, 2-carboxyethyl, methanesulfonylcarbamoylmethyl, benzyl, 4-methoxybenzyl, 4-sulfoethylbenzyl, or 4-sulfopropyloxybenzyl). At least one of A1 and A2 is preferably a group having a sulfo group. It is also preferable that both of A1 and A2 be groups having a sulfo group. This sulfo group can be a salt of an alkaline metal such as sodium or potassium, a salt of an alkaline earth metal such as calcium, or an ammonium salt such as pyridinium, N-methylpyridinium, or tetrabutylammonium.
Z1 represents an atomic group necessary to form a heterocyclic ring selected from the group consisting of substituted or nonsubstituted benzoimidazole, benzoxazole, and naphthoxazole. The ring to be formed is preferably benzoxazole or naphthoxazole.
Z2 represents an atomic group necessary to form a heterocyclic ring selected from the group consisting of substituted or nonsubstituted benzothiazole, benzoselenazole, naphthothiazole, naphthoselenazole, and benzotellurazole. The ring to be formed is preferably benzothiazole, benzoselenazole, or naphthothiazole.
Each of Z1 and Z2 may have a substituent on the benzene ring. Examples of this substituent are those enumerated above for R2 in formula (MC-1). Preferable examples are a halogen atom (a chlorine atom, bromine atom, and iodine atom), an alkyl group (e.g., a 1- to 10-carbon straight-chain, branched or cyclic alkyl group which can contain a substituent and a 7- to 15-total carbon alkyl group substituted with an aryl group which can further contain a substitutent other than the aryl group; specifically, methyl, ethyl, n-propyl, i-propyl, n-butyl, cyclohexyl, methoxymethyl, 2-methoxyethyl, 2-chloroethyl, trifluoromethyl, and hexafluoro-i-propyl; and benzyl, 3-methoxybenzyl, 4-chlorobenzyl, and 4-N,N-dimethylaminobenzyl), an alkoxy group (a 1- to 10-carbon alkoxy group which can contain a substituent; e.g., methoxy, ethoxy, 2-methoxyethoxy, and 2-chloroethoxy), an aryl group (a 6- to 12-carbon aryl group which can contain a substituent; e.g., phenyl, naphthyl, 4-methoxyphenyl, 2-chlorophenyl, hexafluorophenyl, and 4-N,N-dimethylphenyl), an aryloxy group (a 6- to 12-carbon aryloxy group which can contain a substituent; e.g., phenoxy, 2-cholophenoxy, 4-methoxyphenoxy, 4-(2-methoxyethoxy)-phenoxy, and naphthoxy), a cyano group, a hydroxy group, and a carboxyl group. A chlorine atom, an alkyl group, an alkoxy group, an aryl group, and an aryloxy group are particularly preferable.
A3 represents a hydrogen atom, an alkyl group, or an aryl group, which can contain a substituent, for example, an alkyl group substituted with an aryl group. A3 is preferably a hydrogen atom or a non substituted alkyl group, and most preferably, a hydrogen atom or a 1- to 5-carbon alkyl group (e.g., methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, or n-pentyl).
X represents a cation, and n is 1 or 2. When an intramolecular salt is to be formed, n is 1. Examples of the cation represented by X are a metal ion and ammonium salt. Preferable examples are sodium ion, potassium ion, lithium ion, tetramethylammonium ion, N-methylpyridinium ion, triethylammonium ion, tetraethylammonium ion, and pyridinium ion.
Practical compound examples of the sensitizing dye represented by formula (SD-1) will be presented below. However, the present invention is not restricted to these examples. 
In the present invention, the compound represented by formula (SD-1) is contained at a molar ratio of 10% to 100% of the total amount of sensitizing dyes in all the red-sensitive emulsion layers. The ratio of a compound represented by formula (SD-1) is preferably 30 mol % or more, and more preferably, 50 mol % or more.
Any sensitizing dye can be used in combination with the compound represented by formula (SD-1) of the present invention. It is preferable to use the compound represented by formula (SD-1) of the present invention in combination with the sensitizing dyes having the same chemical structure as that of formula (SD-1), except that the terminal atom of the atomic group represented by Z1, which bonds to the carbon atom of xe2x80x94N(xe2x80x94A1)xe2x80x94C(xe2x80x94Z1)xe2x95x90, is a sulfur atom, a selenium atom or a tellurium atom, and the heterocyclic ring formed with Z1 is selected from the group consisting of benzothiazole, naphthothiazole, benzoselenazole, naphthoselenazole, benzotellurazole and naphthotellurazole.
Although any coupler can be contained in red-sensitive emulsion layers of a sensitive material of the present invention, a cyan coupler of a phenol derivative or a pyrroloazole cyan coupler as described in JP-A-9-43790, the disclosure of which is herein incorporated by reference, is preferably contained.
The sensitive material of the present invention has at least one green-sensitive emulsion layer containing the coupler represented by formula (MC-1) of the present invention. Sensitive layers can be arranged by coating a support with at least one blue-sensitive silver halide emulsion layer, at least one green-sensitive silver halide emulsion layer, and at least one red-sensitive silver halide emulsion layer in this order. However, the order can also be changed. When the present invention is applied to a sensitive material for photographing, it is preferable to form red-, green-, and blue-sensitive silver halide emulsion layers in this order from a support. Each color-sensitive layer preferably has a unit configuration including two or more sensitive emulsion layers different in speed. Most preferably, each color-sensitive layer has a three-layered unit configuration including three sensitive emulsion layers, i.e., low-, medium-, and high-speed layers formed in this order from a support.
Emulsion layers differing in speed in the same unit are spectrally sensitized to substantially the same wavelength region. However, the wavelengths which give the maximum values of sensitivity of low- and high-speed emulsion layers can have a difference of about 0 to 15 nm. In a red-sensitive unit of the sensitive material of the present invention, the wavelength which gives the maximum value of sensitivity (by which a cyan density of 0.6 is given) of a low-speed layer is preferably longer by 0 to 10 nm than the wavelength which gives the maximum value of sensitivity (by which a cyan density of 2.0 is given) of a high-speed layer.
The sensitive material of the present invention is spectrally sensitized to blue sensitivity, green sensitivity, and red sensitivity. The wavelength which gives the maximum value of sensitivity of each sensitive layer is preferably 430 to 460 nm for a blue-sensitive layer and 520 to 560 nm for a green-sensitive layer. When a sensitive material of the present invention is spectrally sensitized as described above, a filter dye is preferably used where necessary. To increase color saturation, it is particularly preferable in the present invention to allow an intermediate layer between green- and red-sensitive layers to contain a dye whose wavelength by which the maximum value of absorption is given is 520 to 560 nm.
Next, a sensitive silver halide emulsion layer which does not substantially contribute to image formation but imparts the interimage effect to another layer will be described below. Imparting the interimage effect is to have an effect of suppressing development of another layer as a function of development of this sensitive silver halide emulsion layer.
In the present invention, xe2x80x9cdoes not substantially contribute to image formationxe2x80x9d means that the contribution of this layer to the yellow, magenta, and cyan dye image densities is small. This colorless sensitive emulsion layer can also contain a small amount of a coupler, i.e., can contain 20 mol % or less of a color-forming coupler with respect to couplers which generate the same color and which are contained in the whole material. This layer is preferably a low-color-forming layer which contains 10 mol % or less of such a coupler with respect to couplers which generate the same color, and more preferably, a layer containing no image-forming coupler. Also, this layer preferably contains the compound previously enumerated as a competing compound.
In the present invention, this sensitive silver halide emulsion layer (to be also referred to as the fourth sensitive layer hereinafter) is so spectrally sensitized as to have the maximum value of sensitivity at a wavelength of 480 to 550 nm. The faithfulness of color reproduction can be improved by forming the fourth sensitive layer like this and suppressing development of a red-sensitive layer as a function of development of this fourth sensitive layer.
Also, this layer preferably contains a substance having a development inhibiting function. Known techniques can be used as this substance having a development inhibiting function. Examples are silver iodobromide containing at least 2 to 40 mol % of silver iodide, silver bromochloroiodide, or silver iodide (preferably fine-grain silver iodide having an average grain diameter of 0.05 to 0.20 xcexcm), a development inhibitor (e.g., mercaptotetrazoles, mercaptothiadiazoles, mercaptoxadiazoles, mercaptoimidazoles, mercaptotetrazoles, mercaptobenzothiazoles, mercaptobenzimidazoles, mercaptobenzoxazoles, mercaptothiazoles, benzotriazoles, and benzimidazoles), and a development inhibitor precursor.
The fourth sensitive layer can be formed in any position of a sensitive material. However, this fourth sensitive layer is preferably formed closer to a support than a red-sensitive layer, between red- and green-sensitive layers, or between blue- and green-sensitive layers.
The fourth sensitive layer is most preferably formed between red- and green-sensitive layers or closer to a support than a red-sensitive layer.
Color reproduction by a subtractive color process is possible when each of these sensitive emulsion layers contains a silver halide emulsion sensitive to the corresponding wavelength region and a color coupler for forming a dye which has a complementary color relationship with light to which the emulsion is sensitive. However, the sensitive emulsion layer and the color coupler contained therein need not have the above correspondence. Also, a coupler which generates another hue can be mixed with the coupler for forming a dye which has a complementary color relationship. For example, the shade depicting capability can be improved by mixing a cyan-forming coupler or a black-forming coupler, in addition to a coupler represented by formula (MC-1) of the present invention, in high- and medium-speed layers of a green-sensitive emulsion unit.
Silver halide emulsions to be contained in a sensitive material of the present invention will be described below.
Sensitive silver halide grains for use in the present invention are silver bromide, silver chloride, silver iodide, silver chlorobromide, silver iodochloride, silver iodobromide, or silver bromochloroiodide. The silver halide emulsion can also contain another silver salt, such as silver rhodanate, silver sulfide, silver selenide, silver carbonate, silver phosphate, or organic acid silver, as another grain or as a portion of the silver halide grain. In the present invention, silver iodobromide or silver bromochloroiodide is preferable. More preferably, 0.5 to 30 mol % of silver iodide are contained. Silver iodobromide or silver bromochloroiodide containing 1 to 10 mol % of silver iodide is most preferable.
The silver halide emulsion of the present invention preferably has a distribution or a structure in connection with a halogen composition in its grains. A typical example of such a grain is a core-shell or double structure grain having different halogen compositions in its interior and surface layer as disclosed in, e.g., JP-B-43-13162, JP-A""s-61-215540, 60-222845, 60-143331, or 61-75337, the disclosures of which are herein incorporated by reference. The structure need not be a simple double structure but can be a triple structure or a higher-order multiple structure as disclosed in JP-A-60-222844, the disclosure of which is herein incorporated by reference. It is also possible to bond a thin silver halide having a different composition from that of ia core-shell double-structure grain to the surface of the grain.
The structure to be formed inside a grain need not be the surrounding structure as described above but can be a so-called junctioned structure. Examples of the Functioned structure are disclosed in JP-A""s-59-133540, and 58-108526, EP199,290A2, JP-B-58-24772, and JP-A-59-16254, the disclosures of which are herein incorporated by reference. A crystal to be junctioned can be formed on the edge, the corner, or the face of a host crystal to have a different composition from that of the host crystal. Such a Functioned crystal can be formed regardless of whether a host crystal is uniform in halogen composition or has a core-shell structure.
In a silver iodobromide grain having any of the above structures, it is preferable that the silver iodide content in the core portion be higher than that in the shell portion. In contrast, it is sometimes preferable that the silver iodide content in the core portion be low and that in the shell portion be high. Similarly, in the junctioned-structure grain, the silver iodide content can be high in the host crystal and low in the Functioned crystal and vice versa. The boundary portion between different halogen compositions in a grain having any of the above structures can be either definite or indefinite. It is also possible to positively form a continuous composition change.
In a silver halide grain in which two or more silver halides are present as a mixed crystal or with a structure, it is important to control the distribution of halogen compositions between grains. A method of measuring the distribution of halogen compositions between grains is described in JP-A-60-254032. A uniform halogen distribution between grains is a desirable characteristic. In particular, a highly uniform emulsion having a variation coefficient of 20% or less is preferable. An emulsion having a correlation between a grain size and a halogen composition is also preferable. An example of the correlation is that larger grains have higher iodide contents and smaller grains have lower iodide contents. The opposite correlation or a correlation with respect to another halogen composition can also be selected in accordance with the intended use. For this purpose, it is preferable to mix two or more emulsions having different compositions.
Silver halide grains for use in the present invention can be selected in accordance with the intended use. Examples are a regular crystal not containing a twin plane and crystals explained in Japan Photographic Society ed., The Basis of Photographic Engineering, Silver Salt Photography (CORONA PUBLISHING CO., LTD.), 1st ed., page 163, such as a single twinned crystal containing one twin plane, a parallel multiple twinned crystal containing two or more parallel twin planes, and a nonparallel multiple twinned crystal containing two or more nonparallel twin planes. A method of mixing grains having different shapes is disclosed in U.S. Pat. No. 4,865,964, and this method can be selected as needed. In the case of a regular crystal, it is possible to use a cubic grain constituted by (100) faces, an octahedral grain constituted by (111) faces, or a dodecahedral grain constituted by (110) faces disclosed in JP-B-55-42737 or JP-A-60-222842, the disclosures of which are herein incorporated by reference. It is also possible to use, in accordance with the intended use, an (h11) face grain represented by a (211) face grain, an (hh1) face grain represented by a (331) face grain, an (hk0) face grain represented by a (210) face grain, or an (hk1) face grain represented by a (321) face grain, as reported in Journal of Imaging Science, Vol. 30, page 247, 1986, the disclosures of which are herein incorporated by reference, although the preparation method requires amn: some improvements. A grain having two or more different faces, such as a tetradecahedral grain having both (100) and (111) faces, a grain having (100) and (110) faces, or a grain having (111) and (110) faces, can also be used in accordance with the intended use.
A value obtained by dividing the equivalent-circle diameter of the projected area of a grain by the thickness of that grain is called an aspect ratio that defines the shape of a tabular grain. Tabular grains having aspect ratios higher than 1 can be used in the present invention. Tabular grains can be prepared by the methods described in, e.g., Cleve, Photography Theory and Practice (1930), page 131; Gutoff, Photographic Science and Engineering, Vol. 14, pages 248 to 257, (1970); and U.S. Pat. Nos. 4,434,226, 4,414,310, 4,433,048, and 4,439,520, and British Patent 2,112,157, the disclosures of which are herein incorporated by reference. The use of tabular grains brings about advantages, such as an increase in covering power and an increase in spectral sensitization efficiency due to sensitizing dyes. These advantages are described in detail in U.S. Pat. No. 4,434,226 cited above. The average aspect ratio of 80% or more of the total projected area of grains is preferably 1 to less than 100, more preferably, 2 to less than 20, and most preferably, 3 to less than 10. The shape of a tabular grain can be selected from, e.g., a triangle, a hexagon, and a circle. An example of a preferable shape is a regular hexagon having six substantially equal sides, as described in U.S. Pat. No. 4,797,354, the disclosure of which is herein incorporated by reference.
An equivalent-circle diameter of a projected area is often used as the grain size of a tabular grain. To improve the image quality, grains with an average diameter of 0.6 xcexcm or smaller such as described in U.S. Pat. No. 4,748,106 are preferable. Also, as a shape of a tabular grain, defining the grain thickness to 0.5 xcexcm or less, more preferably, 0.3 xcexcm or less is preferable to improve the sharpness. Grains described in JP-A-63-163451 in which the grain thickness and the distance between twin planes are defined are also preferable.
More desirable results can sometimes be obtained when monodisperse tabular grains with a narrow grain size distribution are used. U.S. Pat. No. 4,797,354 and JP-A-2-838 describe methods of manufacturing monodisperse hexagonal tabular grains with high flatness. EP514,742 describes a method of manufacturing tabular grains whose variation coefficient of a grain size distribution is smaller than 10% by using a polyalkyleneoxide block copolymer. The use of these tabular grains in the present invention is preferable. Grains with a grain thickness variation coefficient of 30% or less, i.e., with a high thickness uniformity are also preferable.
Dislocation lines of a tabular grain can be observed by using a transmission electron microscope. It is preferable to select a grain containing no dislocations, a grain containing several dislocations, or a grain containing a large number of dislocations in accordance with the intended use. It is also possible to select dislocations introduced linearly with respect to a specific direction of a crystal orientation of a grain or dislocations curved with respect to that direction. Alternatively, it is possible to selectively introduce dislocations throughout an entire grain or only to a particular portion of a grain, e.g., the fringe portion of a grain. Introduction of dislocation lines is preferable not only for tabular grains but for a regular crystal grain or an irregular grain represented by a potato-like grain. In the case of these grains, as in the above case, it is preferable to limit the positions of dislocation lines to specific portions, such as the corners or the edges, of a grain.
The grain size of an emulsion used in the present invention can be evaluated in terms of the equivalent-circle diameter of the projected area of a grain obtained by using an electron microscope, the equivalent-sphere diameter of the volume of a grain calculated from the projected area and the thickness of the grain, or the equivalent-sphere diameter of the volume of a grain obtained by a Coulter counter method. It is possible to selectively use various grains from an ultrafine grain having an equivalent-sphere diameter of 0.05 xcexcm or less to a coarse grain having that of 10 xcexcm or more. It is preferable to use a grain having an equivalent-sphere diameter of 0.1 to 3 xcexcm as a sensitive silver halide grain.
In the present invention, it is possible to use a so-called polydisperse emulsion having a wide grain size distribution or a monodisperse emulsion having a narrow grain size distribution in accordance with the intended use. As a measure representing the size distribution, a variation coefficient of either the equivalent-circle diameter of the projected area of a grain or the equivalent-sphere diameter of the volume of a grain is sometimes used. When a monodisperse emulsion is to be used, it is desirable to use an emulsion having a size distribution with a variation coefficient of preferably 25% or less, more preferably, 20% or less, and most preferably, 15% or less.
In order for a sensitive material to satisfy its target gradation, two or more monodisperse silver halide emulsions having different grain sizes can be mixed in the same emulsion layer or applied as different layers in an emulsion layer having essentially the same color sensitivity. It is also possible to mix, or apply as different layers, two or more types of polydisperse silver halide emulsions or monodisperse emulsions together with polydisperse emulsions.
Silver halide grains for use in the present invention can be subjected to at least one of chalcogen sensitization, such as for example, sulfur sensitization and selenium sensitization, and noble metal sensitization such as, for example, gold sensitization and palladium sensitization, and reduction sensitization in any step of the process of manufacturing a silver halide emulsion. The use of two or more different sensitizing methods is preferable. Several different types of emulsions can be prepared by changing the timing at which the chemical sensitization is performed. The emulsion types are classified into: a type in which a chemical sensitization nucleus is embedded inside a grain, a type in which it is embedded in a shallow position from the surface of a grain, and a type in which it is formed on the surface of a grain. In emulsions used in the present invention, the position of a chemical sensitization nucleus can be selected in accordance with the intended use. However, it is generally preferable to form at least one type of a chemical sensitization nucleus near the surface.
It is preferable to perform gold sensitization for emulsions used in the present invention. An amount of a gold sensitizer is preferably 1xc3x9710xe2x88x924 to 1xc3x9710xe2x88x927 mol, and more preferably, 1xc3x9710xe2x88x925 to 5xc3x9710xe2x88x927 mol, per mol of silver halide. A preferable amount of a palladium compound is 1xc3x9710xe2x88x923 to 5xc3x9710xe2x88x927 mol. A preferable amount of a thiocyan compound or a selenocyan compound is 5xc3x9710xe2x88x922 to 1xc3x9710xe2x88x926 mol.
A sulfur sensitizer amount with respect to silver halide grains used in the present invention is preferably 1xc3x9710xe2x88x924 to 1xc3x9710xe2x88x927 mol, and more preferably, 1xc3x9710xe2x88x925 to 5xc3x9710xe2x88x927 mol per mol of a silver halide.
Selenium sensitization is a preferable sensitizing method for emulsions used in the present invention. Known labile selenium compounds are used in this selenium sensitization. Practical examples of the selenium compound are colloidal metal selenium, selenoureas (e.g., N,N-dimethylselenourea and N,N-diethylselenourea), selenoketones, and selenoamides. In some cases, it is preferable to perform the selenium sensitization in combination with one or both of the sulfur sensitization and the noble metal sensitization.
Silver halide emulsions for use in the present invention are preferably subjected to reduction sensitization during grain formation, after grain formation and before or during chemical sensitization, or after chemical sensitization.
The reduction sensitization can be selected from a method of adding reduction sensitizers to a silver halide emulsion, a method called silver ripening in which grains are grown or ripened in a low-pAg ambient at pAg 1 to 7, and a method called high-pH ripening in which grains are grown or ripened in a high-pH ambient at pH 8 to 11. It is also possible to perform two or more of these methods jointly.
The method of adding reduction sensitizers is preferable in that the level of reduction sensitization can be finely adjusted.
Known examples of the reduction sensitizer are stannous chloride, ascorbic acid and its derivative, amines and polyamines, a hydrazine derivative, formamidinesulfinic acid, a silane compound, and a borane compound. In the reduction sensitization of the present invention, it is possible to selectively use these known reduction sensitizers or to use two or more types of compounds together. Preferable compounds as the reduction sensitizer are stannous chloride, thiourea dioxide, dimethylamineborane, and ascorbic acid and its derivative. Although the addition amount of the reduction sensitizers depends upon the emulsion manufacturing conditions and hence must be so selected, an appropriate amount is 10xe2x88x927 to 10xe2x88x923 mol per mol of a silver halide.
Silver halide emulsions for red-sensitive layers of the present invention are spectrally sensitized by methine dyes and the like as described earlier. In addition to the spectral sensitizing dyes, the emulsions can contain dyes having no spectral sensitizing effect or substances which do not substantially absorb visible light and which present supersensitization effect.
The sensitizing dyes can be added to an emulsion at any point in the preparation of an emulsion, which is conventionally known to be useful. Most ordinarily, the addition is performed after completion of chemical sensitization and before coating. However, it is possible to perform the addition at the same timing as addition of chemical sensitizing dyes to perform spectral sensitization and chemical sensitization simultaneously, as described in U.S. Pat. Nos. 3,628,969 and 4,225,666. It is also possible to perform the addition prior to chemical sensitization, as described in JP-A-58-113928, or before completion of formation of a silver halide grain precipitation to start spectral sensitization. Alternatively, as disclosed in U.S. Pat. No. 4,225,666, these compounds can be added separately; a portion of the compounds may be added prior to chemical sensitization, while the remaining portion is added after that. That is, the compounds can be added at any timing during formation of silver halide grains, including the method disclosed in U.S. Pat. No. 4,183,756.
The addition amount can be 4xc3x9710xe2x88x926 to 8xc3x9710xe2x88x923 mol per mol of a silver halide. However, for a more preferable silver halide grain size of 0.2 to 1.2 xcexcm, an addition amount of about 5xc3x9710xe2x88x925 to 2xc3x9710xe2x88x923 mol is more effective.
In silver halide photosensitive materials of the present invention and silver halide photographic emulsions used therein, it is generally possible to use various techniques and inorganic and organic materials described in Research Disclosure Nos. 308119 (1989), 37038 (1995), and 40145 (1997).
In addition, techniques and inorganic and organic materials usable in color photosensitive materials of the present invention can be applied are described in portions of EP436,938A2 and patents cited below.